ACT for Psychological Flexibility, Mindfulness, and Depression

By John M. de Castro, Ph.D.


“Mindfulness is a valuable practice for improving the cognitive symptoms of depression, such as distorted thinking and distractibility. It helps individuals recognize these more subtle symptoms, realize that thoughts are not facts and refocus their attention to the present.” – Margarita Tartakovsky


Mindfulness training in general has been shown to be effective for treating depression. Acceptance and Commitment Therapy (ACT) is a mindfulness based psychotherapy technique that is based upon Cognitive Behavioral Therapy (CBT) and has also been shown to be effective for depression. ACT focuses on the individual’s thoughts, feelings, and behavior and how they interact to impact their psychological and physical well-being. It then works to change thinking to alter the interaction and produce greater life satisfaction. ACT employs mindfulness practices to increase awareness and develop an attitude of acceptance and compassion in the presence of painful thoughts and feelings. Additionally, ACT helps people strengthen aspects of cognition such as in committing to valued living. ACT teaches individuals to “just notice”, accept and embrace private experiences and focus on behavioral responses that produce more desirable outcomes.


As impressive as the effectiveness of many mindfulness based therapies are for depression, they require the supervision of a trained therapist working either with a single individual or in small groups. With the magnitude of the problem of depression, these therapies can only touch a small fraction of depression suffers. Recently the internet has been used to provide therapy to a wide audience. It allows for therapies to be made available to a much larger number of patients over a much larger geographical area. Indeed, ACT provided over the internet has been shown to be effective for depression. It is not known, however, which psychological processes are affected by ACT that work to relieve depression and what participant characteristics are predictive of responsiveness to ACT for depression.


In today’s Research News article “How and for whom does web-based acceptance and commitment therapy work? Mediation and moderation analyses of web-based ACT for depressive symptoms.” See:

or below or view the full text of the study at:

Pots and colleagues investigated potential mediators of ACT therapy for depression delivered over the internet. They randomly assigned patients diagnosed with mild to moderate depression to either receive Acceptance and Commitment Therapy (ACT), an expressive writing treatment, or a wait-list control condition. ACT was delivered over the internet in nine modules that could be completed by participants over nine to twelve weeks. The expressive writing condition was delivered similarly over the internet over the same time frame and involved the participants writing about their recent emotional experiences. The wait-list control participants received no treatments until 6-months later. Measures were taken of depression, mindfulness, psychological flexibility, anxiety, positive mental health and demographic variables prior to and after treatment and 6 and 12 months later.


They found, as previously reported, that ACT produced significant improvements in depressive symptoms that were maintained 6 and 12 months later. ACT produced a large improvement in psychological flexibility and the mindfulness facet of non-reactivity to internal events that were found to mediate the effect on depression. In other words, ACT reduced depression by improving non-reactivity and psychological flexibility.


Pots and colleagues state that “The central therapeutic mechanism in ACT is psychological flexibility, which is the ability to act in accordance with intrinsically motivating values or goals while being in contact with the present moment.” Hence, the results indicate that ACT was successful in producing its desired effect and this increase in the alignment of actions with values is a strong determinant of the reduction in depression. This is thought to be an important aspect of emotion regulation that is so important for allowing emotions to be experienced but not allowing them to produce maladaptive responses. This is also facilitated by not being particularly reactive to these emotions. Hence ACT appears to improve depression by improving the coherence and alignment of beliefs and values with the individual’s actions and emotions.


So, improve psychological flexibility, mindfulness, and depression with Acceptance and Commitment Therapy (ACT).


“It may be wise to not undertake the entire program while in the midst of an episode of clinical depression. Current evidence suggests that it may be prudent to wait until you have gotten the necessary help in climbing out of the depths and are able to approach this new work of working with your thoughts and feelings, with your mind and spirit unburdened by the crushing weight of acute depression.” – Jon Kabat-Zinn, Mark Williams, John Teasdale, and Zindel Segal


CMCS – Center for Mindfulness and Contemplative Studies


This and other Contemplative Studies posts are also available on Google+


Study Summary

Pots WT, Trompetter HR, Schreurs KM, Bohlmeijer ET. How and for whom does web-based acceptance and commitment therapy work? Mediation and moderation analyses of web-based ACT for depressive symptoms. BMC Psychiatry. 2016 May 23;16:158. doi: 10.1186/s12888-016-0841-6.



BACKGROUND: Acceptance and Commitment Therapy (ACT) has been demonstrated to be effective in reducing depressive symptoms. However, little is known how and for whom therapeutic change occurs, specifically in web-based interventions. This study focuses on the mediators, moderators and predictors of change during a web-based ACT intervention.

METHODS: Data from 236 adults from the general population with mild to moderate depressive symptoms, randomized to either web-based ACT (n = 82) or one of two control conditions (web-based Expressive Writing (EW; n = 67) and a waiting list (n = 87)), were analysed. Single and multiple mediation analyses, and exploratory linear regression analyses were performed using PROCESS and linear regression analyses, to examine mediators, moderators and predictors on pre- to post- and follow-up treatment change of depressive symptoms.

RESULTS: The treatment effect of ACT versus the waiting list was mediated by psychological flexibility and two mindfulness facets. The treatment effect of ACT versus EW was not significantly mediated. The moderator analyses demonstrated that the effects of web-based ACT did not vary according to baseline patient characteristics when compared to both control groups. However, higher baseline depressive symptoms and positive mental health and lower baseline anxiety were identified as predictors of outcome across all conditions. Similar results are found for follow-up.

CONCLUSIONS: The findings of this study corroborate the evidence that psychological flexibility and mindfulness are distinct process mechanisms that mediate the effects of web-based ACT intervention. The results indicate that there are no restrictions to the allocation of web-based ACT intervention and that web-based ACT can work for different subpopulations.


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